Device for manually sharpening knives and other blades, comprising interchangeably mounted hard metal plates

ABSTRACT

A device for the manual sharpening of knives and other blades having exchangeably held carbide plates. The exchangeable carbide plates of manual sharpening devices are inserted or pushed into recesses or into a reception of the device body and must be fixed there. This is done by a screw connection in known devices. In the proposed solution, the carbide plates are fixed by snap-latching parts. This represents a favorably technical assembly means to fix the carbide plates fast and reliably and to nevertheless release them again easily and without tools. The snap-latching part can have the form of a cover plate or can engage over the carbide plate like a lug.

The invention relates to a device for the manual sharpening of knivesand other blades having exchangeably held carbide plates.

Devices for the manual sharpening of knives and other blades are alreadyknown in different aspects:

For instance, the devices in accordance with DE 197 03 807 C1 or withU.S. Pat. No. 5,588,340, for example, use only one carbide plate withwhich a knife blade first has to be sharpened from the one side of theblade and then from the other side. Such sharpening devices having asingle carbide plate are suitable for the sharpening of different bladetypes, e.g. of knives, scissors, tools of different types or also skiedges. However, there is the risk that the carbide plate for thesharpening is applied at an incorrect angle or that canting takes place,which results in unsatisfactory sharpening results.

On sharpening with two crossed carbide plates such as are known fromU.S. Pat. No. 6,142,038; U.S. Pat. No. 5,291,805; or U.S. Pat. No.3,149,506, both sides of a blade are processed simultaneously at apre-determined appropriate angle. One error source in handling is thusprecluded. These devices are in particular suitable for the sharpeningof smooth knives without a serrated edge.

Since it is always the same position, namely the V-shaped sharpeningzone in the crossing region of the two carbide plates, which isstrained, wear phenomena of the carbide plates in the sharpening zoneare inevitable in the long term.

For this reason, the carbide plates in accordance with U.S. Pat. No.6,142,038; U.S. Pat. No. 5,291,805; or U.S. Pat. No. 3,149,506 are heldexchangeably so that an exchange or replacement of plates which havebecome unusable can be made. The carbide plates are inserted intosuitably shaped recesses in the device body which fix them downwardlyand laterally. For the remaining fixing, the plates in accordance withU.S. Pat. No. 6,142,038 are screwed individually and the plates inaccordance with U.S. Pat. No. 5,291,805 or U.S. Pat. No. 3,149,506 aresecured by an angled part which is in turn secured to the device body bya screw. In accordance with U.S. Pat. No. 6,142,038, the carbide platesare moreover shaped as rectangles and the recesses are arranged so that,in the case of wear at one position, the same plates can be used againat another position when replaced with one another and/or turned.

The fixing of the carbide plates using a screw shown in U.S. Pat. No.6,142,038; U.S. Pat. No. 5,291,805; and U.S. Pat. No. 3,149,506 has thedisadvantage that, on the exchange of plates by the user, the suitablescrewing tool is not always to hand; that, as on the first assemblyduring manufacture, the holding together of the plurality of still looseindividual parts and the application of the screws is a comparativelytime-consuming and arduous task requiring the right feel; and that inthe course of time the screws can seize unreleasably, on the one hand,or can also become loose, on the other hand.

The sharpeners in accordance with U.S. Pat. No. 5,291,805 or U.S. Pat.No. 3,149,506 are evidently provided for a free guidance of the deviceover a blade; since knives to be sharpened frequently also cannot beplaced onto a work surface in a stable manner due to non-straight handleshapes or back shapes, canting, the sliding off of the device or of theblade, unnecessary use of force or even injuries can occur.

While U.S. Pat. No. 6,142,038 shows an additional part for the secureapplication of the sharpening device during sharpening, this gives thedevice a less practical shape.

It is therefore the object of the present invention to provide a devicefor the manual sharpening of knives and other blades having exchangeablyheld carbide plates with which the reliable fixing of the carbide platesis possible simply and without tools. At the same time, it is the objectof the invention to provide a device whose shape results in a safe andan ergonomically favorable operation.

This object is solved by a device having the features of claim 1.

Advantageous further developments are recited in the dependent claims.Whereas claim 1 is directed to a sharpening device having two crossedcarbide plates, the idea in accordance with the invention of asnap-latching can also be transferred to the fixing of individualcarbide plates in a sharpening device. Independent claim 14 is directedto this.

The snap-latching of a cover plate provided in accordance with theinvention for the fixing of the carbide plates in their recesses avoidsthe disadvantages of a screw connection. It represents a technicallyfavorable assembly means to fix the carbide plates upwardly in a fastand reliable manner and can nevertheless be released easily and withouttools.

Due to the smooth lower side of the gripping and holding part providedin accordance with the invention and to the carbide plates alignedparallel to this smooth lower side, the device can be placed solidlyonto a surface, for example with a projecting functional part at theedge of a table top and can be pressed on with one hand while, with theother hand, a knife to be sharpened is pulled vertically downwardlythrough the V-shaped sharpening zone. The situation of a horizontallydisposed sharpening device and of the vertical blade guidance has provedto be ergonomically favorable and results in good sharpening results.

An embodiment of the invention is represented in the Figures. There areshown:

FIG. 1: a perspective view of the embodiment obliquely from above(broken down into individual parts);

FIG. 2: a perspective view of the embodiment obliquely from below(broken down into individual parts, without the carbide plates);

FIG. 3: a plan view without the snap-latching parts and without thecarbide plates;

FIG. 4: a side view;

FIG. 5 a: a representation of a carbide plate in rectangular shape withtwo bores in the longitudinal axis from above and in cross-section;

FIG. 5 b: a representation of a carbide plate in rectangular shape withtwo off-set bores from above and in cross-section.

FIGS. 1 to 4 show an embodiment of a device for the manual sharpening ofknives and other blades in different views.

The device consists of a shaft-shaped gripping and holding part 1 whichhas a smooth lower side 1 a. A functional part 2 follows at the one endof the gripping and holding part 1 which receives crossed carbide plates3 a, 3 b arranged flatly over one another and surrounds them with theexception of one cut-out 4. The V-shaped sharpening zone 5 at thecrossing point of the carbide plates 3 a, 3 b becomes accessible for theblade to be sharpened through the cut-out 4. The flat side of thecarbide plates 3 a, 3 b is aligned parallel to the smooth lower side 1 aof the gripping and holding part 1 in this process.

This function part 2 is particularly suitable for sharpening smoothknives. For this purpose, the smooth lower side 1 a of the gripping andholding part 1 is placed onto a smooth support, e.g. a table top, andindeed such that the edge of the table top contacts the abutment 2 a.The gripping and holding part 1 which has been placed down can now bepressed onto the support with one hand, with it being possible to makethe pressing down more vigorous using bodyweight while a knife to besharpened is drawn vertically downwardly through the V-shaped sharpeningzone 5.

At the other end of the gripping and holding part 1, a further functionpart 6 is provided which has a single carbide plate 7 with which bladetypes other than smooth knives, e.g. knives with a serrated edge,scissors of all types, tool blades or ski edges, can be sharpened. Thedevice must be freely guided over such blades. The further function part6 has an abutment 6 a with which the carbide plate 7 can be guided alonga blade at the angle typical for scissor blades. This abutment 6 a is atthe same time designed as finger protection in the direction of thegripping and holding part 1 if the device slips or similar mishaps occuron guiding the carbide plate 7 over a blade. This requires the abutment6 a to project by a sufficient amount.

With the exception of the carbide plates 3 a, 3 b, 7, the individualparts of the device are made as plastic injection molded parts. Thegripping and holding part 1 is stiffened and stabilized by honeycombstructures.

The two same-shape carbide plates 3 a, 3 b which have straight-line edgesections with which they form the sharpening zone 5 as a consequence oftheir crossing, are exchangeably inserted in suitably shaped recesses 8a, 8 b in the function part 2. The deeper recess 8 a in this processcuts off part of the flatter recess 8 b so that the required crossing ofthe carbide plates 3 a, 3 b can take place.

The lower contact surface of the recesses 8 a, 8 b can be smooth or(e.g. for technical production reasons) have a structure; it must onlyensure a stable support for the carbide plates 3 a, 3 b. In FIGS. 1 and3, the recess 8 a is smooth at the bottom, whereas in the recess 8 b aweb-like and frame-like structure can be recognized.

The contact surface of the flatter cut-out 8 b lies precisely one platethickness over the contact surface of the deeper recess 8 a. The uppercarbide plate 3 b thus partly comes to rest on the carbide plate 3 ainserted at the bottom.

Spigots 9 project up from the base of the recesses 8 a, 8 b and eachengage as counterpieces into corresponding cut-outs 10 in the carbideplates 3 a, 3 b for the purpose of a secure fixing of the carbide plates3 a, 3 b against lateral positional changes in the recesses 8 a, 8 b. Inthe present embodiment, the cut-outs 10 in the carbide plates 3 a, 3 bare two cylindrical bores in the respective longitudinal axis of theplates, as shown in FIG. 5 a; the spigot shape and its position in therecesses is determined accordingly.

If the carbide plates 3 a, 3 b are of the same shape, have rotationalsymmetry with respect to their outer contour and with respect to thecut-outs 10 and if the position of the recesses 8 a, 8 b and of thespigots 9 in the function part 2 are suitably selected, it is achievedthat respectively different edge sections of the carbide plates 3 a, 3 bform the V-shaped sharpening zone 5 by replacing the carbide plates 3 a,3 b between the recesses and/or by rotating the carbide plates 3 a, 3 b.One carbide plate pair 3 a, 3 b can thus be utilized better before itbecomes unusable due to wear.

A rotation of the carbide plates 3 a, 3 b, which makes the upper sideinto the lower side, is, however, precluded, since the sides of thecarbide plates 3 a, 3 b have to be slightly slanted in the sharpeningzone to develop their sharpening effect. The plate edge at the upperside, which also represents the working edge, thus projects slightlybeyond the plate edge of the lower side (FIGS. 5 a and 5b—cross-sections). The angle of this slant is usually in the range ofapproximately 6°. Since this slight slant can hardly be perceived withthe eye, a marking of the top side is recommended.

In the embodiment of FIGS. 1, 3 and 5 a, the carbide plates 3 a, 3 bhave a rectangular shape and two bores 10 in the longitudinal axis ofthe plate, that is rotational symmetry on a rotation through 180°.

The same rotational symmetry through 180° is also present in the examplein accordance with FIG. 5 b. The two bores 10 are here, however, appliedsymmetrically offset from the longitudinal axis. It thereby becomesimpossible in interaction with the correspondingly likewise offsetspigots to insert the plates into the recesses 8 a, 8 b the wrong wayround, i.e. with swapped upper side and lower side.

In the embodiment with the rectangular plate shape, the position of therecesses 8 a, 8 b in the function part 2 is moreover such that thecrossing point of the carbide plates does not come to lie directly atthe center of a rectangle side. Then, by a changing of the carbideplates between the recesses and/or by a rotation of the carbide platesin four-fold manner, a V-shaped sharpening zone 5 can be establishedfrom different edge sections of the carbide plates 3 a, 3 b.

The upward fixing of the carbide plates 3 a, 3 b inserted into therecesses takes place by means of a cover part 11 with a releasablesnap-latching, as shown in FIGS. 1 and 2. Said cover part has, in theembodiment shown, two molded tabs 12 on one side with which tabs itengages into matching holding slots of the function part 2. The snapbolt 13 on the side of the cover part 11 disposed opposite the tabs 12engages through an opening 14 in the function part 2 and latches into itin a releasable manner.

The different vertical position of the plates 3 a, 3 b arranged over oneanother is balanced in the shape of the cover part 11 by an internalstructure 15 with a correspondingly different contour. As shown in FIG.2, these can be web-like elevations.

For instance, both carbide plates 3 a, 3 b are fixedly held in theirrecesses 8 a, 8 b by the latched cover part 11.

The latched cover part 11 fits flushly into the outer shape of thedevice.

In the further function part 6, a single carbide plate 7 is insertedinto a slot-like reception 16 with a width precisely corresponding tothe plate thickness. For the fixing of the carbide plate 7 in the slot16, a snap-latching part 17 is again provided which engages over thecarbide plate 7 from the front in a central, lug-like and flush mannerand of which at least one snap lug 18 latches removably in the furtherfunction part 6 behind the carbide plate 7 such that it pulls along thecarbide plate 7 on the pulling out of the released snap-latching part17.

The snap-latching part 17 naturally covers only a narrow strip of theuseful edge of the carbide plate 7.

The outwardly projecting section of the snap-latching part 17 can bemade as a further abutment for an object with a blade to be sharpened,for example as a 90° abutment for the sharpening of ski edges.

1. A device for the manual sharpening of knives and other blades bymeans of two crossed carbide plates (3 a, 3 b) arranged flatly over oneanother, comprising a shaft-shaped gripping and holding part (1) whichhas a smooth lower side (1 a) with which the device can be placedsolidly on a smooth support in use; a function part (2) at the onelongitudinal end of the gripping and holding part (1) which receives thecarbide plates (3 a, 3 b) and surrounds them with the exception of acut-out (4) through which a V-shaped sharpening zone (5) at the crossingpoint of the carbide plates (3 a, 3 b) becomes accessible for the bladeto be sharpened; two same shape carbide plates (3 a, 3 b) which havestraight-line edge sections with which they form the V-shaped sharpeningzone (5) due to their crossing, which each have at least onethrough-going cutout (10) and which have rotational symmetry withrespect to their outer contour and with respect to the cut-outs (10); afirst recess (8 a) in the function part (2) into which the flat side ofthe one carbide plate (3 a) is exchangeably inserted parallel to thesmooth lower side (1 a) of the gripping and holding part (1); a secondrecess (8 b) in the function part (2) into which the flat side of theother carbide plate (3 b) is exchangeably inserted parallel to thesmooth lower side (1 a) of the gripping and holding part (1); spigots(9) which each project as counterpieces to the at least one cut-out (10)in the carbide plates (3 a, 3 b) out of the base of the recesses (8 a, 8b) to fix the carbide plates (3 a, 3 b) against the lateral positionalchanges; a cover part (11) insertable into the function part (2) andhaving a releaseable snap-latching to upwardly fix the carbide plates (3a, 3 b) inserted into the recesses (8 a, 8 b); such a position of therecesses (8 a, 8 b) in the function part (2) that, by changing thecarbide plates (3 a, 3 b) between the recesses (8 a, 8 b) and/or byrotation of the carbide plates (3 a, 3 b) in at least four-fold manner,different edge sections of the carbide plates (3 a, 3 b) for theV-shaped sharpening zone (5).
 2. A device in accordance with claim 1,wherein the sides of the carbide plates (3 a, 3 b) are slightly slantedat the straight-line edge sections such that the upper edge projectsslightly beyond the lower edge, with the upper edge representing theworking edge.
 3. A device in accordance with claim 2, wherein the slantangle amounts to approximately 6°.
 4. A device in accordance with claim2, wherein the upper side is marked.
 5. A device in accordance withclaim 2, wherein the at least one cut-out (10) in the carbide plates (3a, 3 b) and the spigots (9) in the recesses (8 a, 8 b) are arrangedand/or designed such that the carbide plates (3 a, 3 b) are notinsertable into the recesses (8 a, 8 b) with the upper side and thelower side the wrong way round.
 6. A device in accordance with claim 1,wherein the cut-outs (10) consist of two bores and, accordingly, twospigots (9) are provided per recess (8 a, 8 b).
 7. A device inaccordance with claim 1, wherein the cover part (11) has two molded tabs(12) at one side, which engage into corresponding holding slots of thefunction part (2), and, at the opposite side, has a snap bolt (13) whichengages through an opening (14) in the function part (2) and releasablylatches in it.
 8. A device in accordance with claim 1, wherein anabutment (2 a) is formed in the transition region from the function part(2) to the gripping and holding part (1) as a termination of its smoothlower side (1 a).
 9. A device in accordance with claim 1, wherein afurther function part (6) having a single carbide plate (7) is providedat the end of the gripping and holding part (1) disposed opposite thefunction part (2).
 10. A device in accordance with claim 9, wherein anabutment (6 a) with which the carbide plate (7) can be guided along ablade at the angle typical for scissor blades is provided at the furtherfunction part (6).
 11. A device in accordance with claim 10, wherein theabutment (6 a) is simultaneously formed as a finger protection in thedirection of the gripping and holding part (1).
 12. A device inaccordance with claim 9, wherein the single carbide plate (7) in thefurther function part (6) is exchangeably pushed into a slot-likereception (15) having a width precisely corresponding to the platethickness and is fixed by a snap-latching part (17) which engages overthe carbide plate (7) from the front in a central, lug-like and flushmanner and of which at least one snap-lug (18) releasably latches in thefurther function part (6) behind the carbide plate (7).
 13. A device inaccordance with claim 12, wherein the outwardly projecting section ofthe snap-latching part (17) is made as an abutment, preferably as a 90°abutment for sharpening ski edges.
 14. A device for the manualsharpening of knives and other blades by means of a carbide plate whichexchangeably pushed into a slot-like reception in the device body havinga width precisely corresponding to the plate thickness and is fixed by asnap-latching part which engages over the carbide plate from the frontin a central, lug-like and flush manner and from which at least onesnap-lug releasably latches in the device body behind the carbide plate.15. A device in accordance with claim 3, wherein the upper side ismarked.
 16. A device in accordance with claim 3, wherein the at leastone cut-out (10) in the carbide plates (3 a, 3 b) and the spigots (9) inthe recesses (8 a, 8 b) are arranged and/or designed such that thecarbide plates (3 a, 3 b) are not insertable into the recesses (8 a, 8b) with the upper side and the lower side the wrong way round.
 17. Adevice in accordance with claim 4, wherein the at least one cut-out (10)in the carbide plates (3 a, 3 b) and the spigots (9) in the recesses (8a, 8 b) are arranged and/or designed such that the carbide plates (3 a,3 b) are not insertable into the recesses (8 a, 8 b) with the upper sideand the lower side the wrong way round.
 18. A device in accordance withclaim 15, wherein the at least one cut-out (10) in the carbide plates (3a, 3 b) and the spigots (9) in the recesses (8 a, 8 b) are arrangedand/or designed such that the carbide plates (3 a, 3 b) are notinsertable into the recesses (8 a, 8 b) with the upper side and thelower side the wrong way round.
 19. A device in accordance with claim 2,wherein the cut-outs (10) consist of two bores and, accordingly, twospigots (9) are provided per recess (8 a, 8 b).
 20. A device inaccordance with claim 3, wherein the cut-outs (10) consist of two boresand, accordingly, two spigots (9) are provided per recess (8 a, 8 b).